1. Field of the Invention
The Present Invention relates generally to an optical ferrule assembly.
2. Description of the Related Art
Conventionally, in optical connectors used in optical communications and the like, it has been proposed to use an optical ferrule assembly having a mechanical splice structure therein, in order that an optical fiber can be easily connected for a short time at the laying site or the like (refer to, for example, Japanese Patent Applications Laid-Open (Kokai) Nos. 2005-114860 and 2005-241956).
FIG. 18 is a cross sectional view showing the structure of a conventional optical ferrule assembly. In FIG. 18, reference numeral 301 denotes a ferrule body in the optical ferrule assembly, and a mid-portion thereof is semi-cylindrically cut out to form a notch part 302. Also, a cylindrical guide part 303 is formed at the rear part of the ferrule body 301, and a ring-shaped flange part 304 is fixed to the outer periphery of the ferrule body 301. An optical fiber loading hole 306 extending from the front end surface to the inside is formed centrally of the ferrule body 301, and an optical fiber core cable 307 is fixed by adhesive in the optical fiber loading hole 306. The notch part 302 is provided with a first optical fiber inserting groove 308 of semicircular cross section aligned with the optical fiber loading hole 306. The guide part 303 is provided with an optical fiber inserting hole 309 of semicircular cross section aligned with respect to the first optical fiber inserting groove 308.
A semi-cylindrical retainer 310 is placed in the notch part 302. The lower surface of the retainer 310 is provided with a second optical fiber inserting groove 311 of V-like cross section. The second optical fiber inserting groove 311 cooperates with the first optical fiber inserting groove 308 to construct an optical fiber inserting path. A ring member 312 is slidably fitted on the outer periphery of the guide part 303. The ferrule body 301 has an inlet for refractive index matching agent 317. A refractive index matching agent 318 impregnated from the inlet for index matching agent 317 is adhered in advance on the rear end of the optical fiber core cable 307 in the optical fiber inserting path.
When inserting another optical fiber core cable into the above-mentioned optical ferrule assembly, the optical fiber core cable is inserted from the rear end surface of the ferrule body 301 into the optical fiber inserting hole 309. In this case, some clearance is left between the upper surface of the notch part 302 and the lower surface of the retainer 310. Therefore, the cross section of the optical fiber inserting path to be formed between the first optical fiber inserting groove 308 and the second optical fiber inserting groove 311 is sufficiently large with respect to the optical fiber core cable. It is therefore possible to smoothly insert another optical fiber core cable from the optical fiber inserting hole 309 into the optical fiber inserting path, thereby bringing the tip thereof into contact with the rear end of the optical fiber core cable 307.
Subsequently, when the ring member 312 is advanced, the lower surface of the retainer 310 can be pressed against the upper surface of the notch part 302 by means of the ring member 312. As the result, the other optical fiber core cable is held between the first optical fiber inserting groove 308 and the second optical fiber inserting groove 311, and fixed to the ferrule body 301. The rear end of the upper surface of the retainer 310 is provided with a taper portion 316, enabling the ring member 312 to smoothly be advanced to a position on the ring member 312.
However, in the above-mentioned conventional optical ferrule assembly, smooth insertion of the optical fiber core cable requires that the clearance be left between the upper surface of the notch part 302 and the lower surface of the retainer 310. To this end, a resilient member such as resin is interposed between the upper surface of the notch part 302 and the lower surface of the retainer 310, or a resilient projection is provided on the lower surface of the retainer 310 formed of a resilient member such as resin. This may increase the number of parts of the optical ferrule assembly and complicate the construction of the retainer 310.